docs: def populate_regions(self, tectonic_region_dict):
          '''
          Populates the tectonic region from the list of dictionaries, where each
          region is a dictionary of with the following format::
  
           region = {'Shear_Modulus': [(val1, weight1), (val2, weight2), ...],
                     'Displacement_Length_Ratio': [(val1, weight1), ...],
                     'Magnitude_Scaling_Relation': [(val1, weight1), ...]}
          '''
          for tect_reg in tectonic_region_dict:
              if 'Shear_Modulus' in tect_reg.keys():
                  shear_modulus = tect_reg['Shear_Modulus']
              else:
                  shear_modulus = DEFAULT_SHEAR_MODULUS
  
              if 'Displacement_Length_Ratio' in tect_reg.keys():
                  disp_length_ratio = tect_reg['Displacement_Length_Ratio']
              else:
                  disp_length_ratio = DEFAULT_DLR
  
              if 'Magnitude_Scaling_Relation' in tect_reg.keys():
                  scaling_relation = tect_reg['Magnitude_Scaling_Relation']
              else:
                  scaling_relation = DEFAULT_MSR
  
              self.regionalisation.append(
                  TectonicRegion(
                      tect_reg['Code'], tect_reg['Name'],
                      shear_modulus, disp_length_ratio, scaling_relation))
              self.key_list.append(tect_reg['Name'])